Some questions about Randall Sundrum model

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In summary, the Randall Sundrum Model is a theory that expands the four-dimensional Minkowskian spacetime by adding a fifth compact dimension on an orbifold. This model includes two 3-branes, the UV Brane and the IR or TeV brane, which are responsible for the extra dimension. Only gravity can propagate through this dimension. The metric of this model is non-factorizable, with an exponential factor known as the warp factor that explains the large hierarchy between the Plank and weak scale. For a simpler explanation of this model, Raman Sundrum's lectures on extra dimensions are recommended. Additionally, for those interested in further understanding of this model, a good introduction can be found in the paper "Introduction to Randall
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maani
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Hi, I have been studied the Randall Sundrum Model for a while (original paper: hep-ph/9905221), but I don't come forward with it. So far I understood:

In the RS model the four dimensional Minkowskian spacetime is expanded by a fifth dimension, which is compactified on an orbifold S1/Z2.
What is an orbifold? What is Z2? And why on orbifold?
On the fixed points of this orbifold are located two 3-branes: the UV Brane, where the gravitation reside, and the IR or TeV brane, which is our universe with all SM particles.They form the border of the extra dimension. Only the gravitation can propagate through the extra dimension. The extra dimension is curved, the metric is given by ds2=e-2kr[tex]\phi[/tex]g[tex]\mu\nu[/tex]dx[tex]\mu[/tex]dx[tex]\nu[/tex]-r2d[tex]\phi[/tex]2

The metric is non factorizable. What does it mean? And why is this important? The exponential factor is called warp factor and is responsible for the large hierarchy between Plank and weak scale.

Well this is so war. I guess I need something like "RS model for dummies". Can anybody recommend me some paper, where the model is simply explained?

Thanks a lot in advance!
 
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Try Raman Sundrum's 'Extra Dimensions Lecture 3'
http://www.pha.jhu.edu/~sundrum/presentations.html [Broken]

Or his TASI 2004 Lectures: To the Fifth Dimension and Back
http://arxiv.org/abs/hep-th/0508134
 
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Hi I found the answers I needed. For those who are interested in RS models or Extra Dimensions this is a very good introduction: http://arxiv.org/abs/hep-ph/0409309
 

1. What is the Randall Sundrum model?

The Randall Sundrum (RS) model is a theoretical framework in particle physics that proposes a solution to the hierarchy problem, which is the large discrepancy between the observed strength of gravity and the other fundamental forces. It suggests that our universe may have more than three spatial dimensions, with one of them being compactified and hidden from our perception.

2. How does the RS model solve the hierarchy problem?

The RS model introduces a warped extra dimension, where the strength of gravity is diluted by the warping factor. This allows for a lower fundamental scale compared to the Planck scale, which is the scale at which gravity becomes comparable to the other forces. The warped extra dimension also provides a natural mechanism for the hierarchy between the electroweak and Planck scales.

3. What are the implications of the RS model for particle physics?

The RS model predicts the existence of Kaluza-Klein (KK) particles, which are excitations of the known particles in higher dimensions. These KK particles could be detected at high energy colliders, such as the Large Hadron Collider (LHC), providing evidence for the existence of extra dimensions. The RS model also offers a possible explanation for the origin of dark matter.

4. Has the RS model been tested experimentally?

While there is currently no direct evidence for the RS model, it has been extensively studied and tested through theoretical calculations and simulations. The LHC has also searched for KK particles predicted by the RS model, but no conclusive evidence has been found yet. Further experiments and observations may shed light on the validity of the RS model.

5. Are there any criticisms of the RS model?

One major criticism of the RS model is that it does not address the cosmological constant problem, which is the large discrepancy between the observed value of the cosmological constant and its theoretical prediction. It also faces challenges in reconciling with other theories, such as supersymmetry. However, these criticisms have not been definitively proven to be flaws in the RS model and further research is needed to fully understand its implications.

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